Depth diaphragms are components of x-ray equipment and serve to variably restrict the bundle of rays to the necessary field size. The undesired portions of the rays are absorbed by the diaphragm blades, which are usually made of lead. To set the depth diaphragm, the desired field size can be simulated by means of a light bundle. X-ray equipment is usually fitted with depth diaphragms having two pairs of lead blades for adjusting the height and width of the image display. Said pairs of lead blades are controlled symmetrically with respect to the center of the detector and isocentrically with respect to the x-ray tube. The plate-shaped diaphragm blades cannot, however, be enlarged at will as that would also increase the size of the depth diaphragm, resulting in, for instance, angulation limiting on a C-arch of the x-ray device.